Here you find definitions of important terms that are used within this platform. The reference is given for each definition, if the definition does not stem from the ci:grasp context itself.

A list of relevant literature used for ci:grasp can be found in our bibliography.
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Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities. Various types of adaptation can be distingiushed, including anticipatory, autonomous and planned adaptation. (IPCC, AR4)

Adaptation Project

An adaptation project is an applied or planned action that aims to reduce the consequences of climate hazards and climate variability and is defined for a specific geographical region.

Agricultural production loss

Potential loss of agricultural production.


Baseline period

Any climate scenario must adopt a reference baseline period from which to calculate changes in climate. This baseline data set serves to characterize the sensitivity of the exposure unit to present-day climate and usually serves as the base on which data sets that represent climate change are constructed. Among the possible criteria for selecting the baseline period (IPCC, 1994), it should be representative of the present-day or recent average climate in the study region and of a sufficient duration to encompass a range of climatic variations, including several significant weather anomalies (e.g., severe droughts or cool seasons).

A popular climatological baseline period is a 30-year "normal" period, as defined by the WMO. The current WMO normal period is 1961-1990, which provides a standard reference for many impact studies. Note, however, that in some regions, observations during this time period may exhibit anthropogenic climate changes relative to earlier periods. [28]


Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit)


Carbon Dioxide (CO2)

Carbon dioxide exists naturally in the atmosphere and is one of the most important greenhouse gases. Anthropogenic activities influence its concentration. Since the industrialization in the 19th century, the CO2 concentration in the atmosphere has increased in an unnatural and fast rate and is held responsible for a great part of the global warming today.


CCSM3.0 (Community Climate System Model version 3.0) is a general circulation model (GCM) from the National Center for Atmospheric Research (NCAR, [3], [4].


CM2.1 is a general circulation model (-> GCM) from Geophysical Fluid Dynamics Laboratory, NOAA [5]


Climate in a narrow sense is usually defined as the 'average weather', or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system. The classical period of time is 30 years, as defined by the World Meteorological Organization (WMO). (IPCC, AR4)

Climate Change

Climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity. This usage differs from that in the United Nations Framework Convention on Climate Change (UNFCCC), which defines 'climate change' as: 'a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods'. (IPCC, AR4)

Climate Prediction

A prediction is a forecast to e.g. a future climatic condition. With knowledge of the past and actual climatic conditions and with aid of models, it is tried out to give a statement what will happen in the future. This information shall help to plan e.g. adaptation measures. [20]

Climate Projection

A projection is a potential future evolution of a quantity or set of quantities, often computed with the aid of a model. Projections are distinguished from predictions in order to emphasize that projections involve assumptions concerning, for example, future socioeconomic and technological developments that may or may not be realized, and are therefore subject to substantial uncertainty. [20]

Climate Variability

Climate variability refers to variations in the mean state and other statistics (such as standard deviations, statistics of extremes, etc.) of the climate on all temporal and spatial scales beyond that of individual weather events. Variability may be due to natural internal processes within the climate system (internal variability), or to variations in natural or anthropogenic external forcing (external variability). (IPCC, AR 4)


Climatic Research Unit, Norwich, UK

The Climatic Research Unit is widely recognised as one of the world's leading institutions concerned with the study of natural and anthropogenic climate change.

The Unit has developed a number of the data sets widely used in climate research, including the global temperature record used to monitor the state of the climate system, as well as statistical software packages and climate models. [14]



The Data Envelopment Analysis (DEA) is a method to measure the efficiency of so called Decision Making Units (DMUs).


A Digital Elevation Model (DEM) is a digital map of elevation data. These maps are raster data, meaning that they are made up of equally sized gridded cells each with a unique elevation. [17]


Abbreviation for the time period covering the months December, January, February (winter). Drought The phenomenon that exists when precipitation is significantly below normal recorded levels, causing serious hydrological imbalances that often adversely affect land resources and production systems. (IPCC, AR4)



ECHAM5 is a general circulation model (GCM) from Max-Planck-Institute of Meteorology [6]


ECHO-G is a general circulation model (GCM) from Meteorological Institute, University of Bonn and others [7]

Economic impact

Specific economic impact:

The monetary valuation of the damages of a specific impact.

Overall economic impact:

The cumulated monetary value of the damages associated with all impacts from the corresponding impact chain that can be assigned with a monetary value.


Flooded area

Extent of land that is temporarily flooded. (in km2, %)



GADM is a spatial database of the location of the world's administrative areas. [21]


Global/General Circulation Model

Numerical models to represent physical processes in the atmosphere, ocean, cryosphere and land surface. GCMs are used to simulate the global climate system's response to increasing greenhouse gas concentrations. Examples for GCMs are CCSM3.0, CM2.1, ECHAM5, ECHO-G or HadCM3 [2]


The gross domestic product (GDP) is a measure of a country's overall economic output. It is the market value of all final goods and services made within the borders of a country in a year. It is often used for measuring the standard of living. [22]


Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, USA The Geophysical Fluid Dynamics Laboratory (GFDL) develops and uses mathematical models and computer simulations to improve our understanding and prediction of the behavior of the atmosphere, the oceans, and climate. [9]


German Society for International Cooperation (Deutsche Gesellschaft für internationale Zusammenarbeit)



HadCM3 is a general circulation model (GCM) from Hadley Centre for Climate Prediction and Research, Met Office, United Kingdom [8]

Hydrological drought

Hydrological drought is associated with the effects of periods of precipitation (including snowfall) shortfalls on surface or subsurface water supply (i.e., streamflow, reservoir and lake levels, ground water). The frequency and severity of hydrological drought is often defined on a watershed or river basin scale. Although all droughts originate with a deficiency of precipitation, hydrologists are more concerned with how this deficiency plays out through the hydrologic system. Hydrological droughts are usually out of phase with or lag the occurrence of meteorological and agricultural droughts. It takes longer for precipitation deficiencies to show up in components of the hydrological system such as soil moisture, streamflow, and ground water and reservoir levels. As a result, these impacts are out of phase with impacts in other economic sectors. For example, a precipitation deficiency may result in a rapid depletion of soil moisture that is almost immediately discernible to agriculturalists, but the impact of this deficiency on reservoir levels may not affect hydroelectric power production or recreational uses for many months. Also, water in hydrologic storage systems (e.g., reservoirs, rivers) is often used for multiple and competing purposes (e.g., flood control, irrigation, recreation, navigation, hydropower, wildlife habitat), further complicating the sequence and quantification of impacts. Competition for water in these storage systems escalates during drought and conflicts between water users increase significantly. [27]

Hydrological year

Generally, 1 October to 30 September in the Northern Hemisphere, 1 July to 30 June in the Southern Hemisphere; the annual cycle that is associated with the natural progression of the hydrologic seasons. It commences with the start of the season of soil moisture recharge, includes the season of maximum runoff (or season of maximum groundwater recharge), if any, and concludes with the completion of the season of maximum evapotranspiration (or season of maximum soil moisture utilization). [26]



The effects of climate change on natural and human systems. Depending on the consideration of adaptation, one can distinguish between potential impacts and residual impacts: Potential impacts: all impacts that may occur given a projected change in climate, without considering adaptation. Residual impacts: the impacts of climate change that would occur after adaptation. (IPCC AR4, Glossary)

Impact chain

Impact chains display the interrelationship of different impacts that are caused by initial drivers of climate change.

Infrastructure at risk

Extent of land, that is permanently lost. (in km2, %)


The Intergovernmental Panel on Climate Change (IPCC) is an organization of the United Nations to assess the risks of global warming and to collect and edit all scientific results with regard to the research field of climate change. [18]



Abbreviation for the time period covering the months June, July, August (summer).


Land loss

Extent of land, that is permanently lost. (in km2, %)



Abbreviation for the time period covering the months March, April, May (spring).

Meteorological drought

A Meteorological drought is mainly a prolonged deficit of precipitation. [20]


An anthropogenic intervention to reduce the anthropogenic forcing of the climate system; it includes strategies to reduce greenhouse gas sources and emissions and enhancing greenhouse gas sinks. (IPCC,AR4)


Meteorological Institute, University of Bonn, Germany [10]


Max-Planck-Institute for Meteorology, Hamburg, Germany The Max Planck Institute for Meteorology (MPI-M) is an internationally renowned institute for climate research. Its goal is to understand the changing climate of our Earth. [11]



Nitrous oxide is a greenhouse gas like CO2.


National Center for Atmospheric Research, Boulder (CO), USA

The National Center for Atmospheric Research (NCAR) is a federally funded research and development center devoted to service, research and education in the atmospheric and related sciences. NCAR's mission is to understand the behavior of the atmosphere and related physical, biological and social systems.

No-regret option

A policy (or action) that would generate net social and/or economic benefits irrespective of whether or not anthropogenic climate change occurs (IPCC, 2007) [12]


People at risk of migration

Number of people that are at risk of permanent relocation.


Potsdam Institute for Climate Impact Research [24]


Purchasing Power Parity. An economic theory that estimates the amount of adjustment needed on the exchange rate between countries in order for the exchange to be equivalent to each currency's purchasing power. [23]


Precipitation is any condensed water which falls down on the earth's surface, also as snow or directly condensed on any objects as dew or rime.



A plausible and often simplified description of how the future may develop, based on a coherent and internally consistent set of assumptions about driving forces and key relationships. Scenarios may be derived from projections, but are often based on additional information from other sources, sometimes combined with a 'narrative storyline'. (IPCC, AR4)

Sea-level rise (SLR)

The sea level can change, both globally and locally, due to (i) changes in the shape of the ocean basins, (ii) changes in the total mass of water and (iii) changes in water density. Factors leading to sea level rise under global warming include both increases in the total mass of water from the melting of land-based snow and ice, and changes in water density from an increase in ocean water temperatures and salinity changes. Relative sea level rise occurs where there is a local increase in the level of the ocean relative to the land, which might be due to ocean rise and/or land level subsidence. ha: hectare, a square of 100x100 meters (10.000 m2). [20]


Abbreviation for the time period covering the months September, October, November (autumn).


The Standardized Precipitation Index is a relatively new drought index, developed 1993 by McKee, Doesken and Kleist, which is based only on the probability of precipitation for any time scale. The index is standardized so that an index of zero indicates the median precipitation amount (50 % of the historical precipitation amount is below and 50 % is above the median). A negative value stands for drought conditions, a positive value stands for wet conditions. [15], [16]

SRES Scenarios

SRES refers to the scenarios described in the IPCC Special Report on Emissions Scenarios (SRES, 2000). The SRES scenarios are grouped into four scenario families (A1, A2, B1 and B2) that explore alternative development pathways, covering a wide range of demographic, economic and technological driving forces and resulting GHG emissions. The SRES scenarios do not include additional climate policies above current ones. The emissions projections are widely used in the assessments of future climate change, and their underlying assumptions with respect to socio-economic, demographic and technological change serve as inputs to many recent climate change vulnerability and impact assessments.

The A1 storyline assumes a world of very rapid economic growth, a global population that peaks in mid-century and rapid introduction of new and more efficient technologies. A1 is divided into three groups that describe alternative directions of technological change: fossil intensive (A1FI), non-fossil energy resources (A1T) and a balance across all sources (A1B)

B1 describes a convergent world, with the same global population as A1, but with more rapid changes in economic structures toward a service and information economy. B2 describes a world with intermediate population and economic growth, emphasising local solutions to economic, social, and environmental sustainability.

A2 describes a very heterogeneous world with high population growth, slow economic development and slow technological change.

No likelihood has been attached to any of the SRES scenarios. [1]


Shuttle Radar Topography Mission. The SRTM data were recorded during the STS-99 Shuttle Radar Topography Mission (SRTM) in February 2000 from space. They are used to create a uniform, high-resolution digital terrain model of the Earth's surface. Because of the resolution of the scanned grids of 90 x 90 meters, it is sometimes called SRTM90. [25]


A climate-related variable that can cause impacts on human activities and the environment.



United Kingdom Meteorology Office, Exeter, UK

The Met Office is the UK's National Weather Service and has a long history of weather forecasting and has been working in the area of climate change for more than two decades. [13]

Urban damages

The extent to which the economic activity in urban areas is potentially constrained. (in GDP)



Vulnerability is the degree to which a system is susceptible to, and unable to cope with, adverse effects of climate change, including climate variability and extremes. Vulnerability is a function of the character, magnitude, and rate of climate change and variation to which a system is exposed, its sensitivity, and its adaptive capacity. (IPCC AR4)


Walter Climate Diagram

A diagram of climatic conditions at a particular location, depicting seasonal variations as well as mean values in order to provide a succinct and easily accessible summary of a local climate. ci:grasp provides interactive access to a simplified version of such diagrams for gridded monthly data generated by various GCMs and for several scenarios to allow for intuitive comparison of climatic conditions for different locations and time periods.

WCRP CMIP3 Multi Model

The Coupled Model Intercomparison Project (CMIP) of the World Climate Research Programme (WCRP) Committee started in the mid-1990s. The objective of this project is the exchange of knowledge about climate modeling and easier access to model data for separate research groups. [19]

Win-Win option

A situation, outcome or action that benefits two parties, or that has two distinct benefits. In terms of adaptation this corresponds to an action that alleviates climate impacts and at the same time is beneficial for other parts of the system.